Cold-process soap has a cost trap built into it: the bar you sell today was made 4–6 weeks ago, and the cost of the oils tied up in curing racks for that entire time rarely makes it into anyone's pricing. Add labour, lye, and packaging, and most handmade soap sellers are pricing on instinct rather than on real numbers.
A typical cold-process recipe blends several oils for lather, hardness and conditioning — commonly olive, coconut, and palm or a palm alternative, sometimes with shea or cocoa butter. Bulk oil prices in 2026 run roughly £2.20–£3.80/kg for olive oil, £2.00–£3.20/kg for coconut oil, and £4.50–£7.50/kg for shea butter. A standard 1kg oil batch (making roughly 10–12 bars at 90–100g each) typically costs £2.80–£4.50 in oils and butters — around £0.25–£0.40 per bar.
Sodium hydroxide (lye) costs £2–£3.50/kg and a standard batch uses 130–150g, putting lye cost at roughly £0.25–£0.35 per batch — a small but non-zero cost, plus distilled or filtered water if your tap water isn't suitable.
This is often the largest single cost. Fragrance oils run £8–£15 per 100ml and essential oils considerably more (£15–£40+/100ml for popular scents like lavender or eucalyptus). A standard fragrance load of 3–5% of oil weight on a 1kg batch means 30–50g of fragrance — £2.50–£6.00 per batch, or £0.20–£0.55 per bar.
Clays, activated charcoal, botanicals, mica or natural colourants, plus oatmeal or exfoliants for speciality bars add £0.10–£0.35 per bar depending on how elaborate the recipe is.
A printed wrap or box, ingredient label (a legal requirement for cosmetic products sold in the UK/EU under the Cosmetic Products Regulation), and any ribbon or branding typically runs £0.40–£0.90 per bar.
Cold-process soap needs 4–6 weeks to cure before it's ready to sell — during which the oils, lye, and your workspace are tied up producing nothing sellable yet. This is a real opportunity cost, not just a waiting period: it limits how many batches you can have "in progress" at once and effectively caps your production capacity per square foot of curing rack space.
A batch — measuring, mixing, pouring, cutting once unmoulded, and periodic turning during cure — takes roughly 45–75 minutes of active time for a 10–12 bar batch, plus 5–10 minutes per bar for wrapping and labelling once cured. At £15/hour, that's £1.00–£1.60 per bar in labour across the whole process.
| Cost Element | Simple Bar | Speciality / Botanical Bar |
|---|---|---|
| Oils & butters | £0.32 | £0.40 |
| Lye | £0.03 | £0.03 |
| Fragrance / essential oil | £0.30 | £0.50 |
| Additives / colourant | £0.10 | £0.30 |
| Packaging & label | £0.55 | £0.75 |
| Labour | £1.20 | £1.50 |
| Total cost | £2.50 | £3.48 |
| Retail price (40% margin) | £4.17 | £5.80 |
A basic bar needs to sell for around £4.20 to hit a proper margin; a botanical or speciality bar closer to £5.80–£6.50. Selling below these numbers — common among new sellers matching the lowest price on Etsy — usually means working for less than minimum wage once labour is properly counted.
Formulate recipes, calculate lye with a built-in safety check, manage ingredient costs, and price your batches with confidence — cure-time and all.
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